Bug 1514898 - Distorted fonts in Qt5 applications with NVIDIA Card when subpixel rendering is enabled
Summary: Distorted fonts in Qt5 applications with NVIDIA Card when subpixel rendering ...
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: qt5-qtbase
Version: 27
Hardware: Unspecified
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Than Ngo
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-11-19 10:35 UTC by Alexander Korsunsky
Modified: 2018-11-30 21:55 UTC (History)
6 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2018-11-30 21:55:06 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)
TeXstudio with distorted font (48.90 KB, image/png)
2017-11-19 10:35 UTC, Alexander Korsunsky
no flags Details

Description Alexander Korsunsky 2017-11-19 10:35:57 UTC
Created attachment 1355082 [details]
TeXstudio with distorted font

Description of problem:

When using Qt5 applications, the font is often distorted and has a green shade (see attachment).

I tested this with 3 different Qt5 apps:

 - vlc
 - TeXstudio
 - Mendeley

I also tested Qt4 apps, like Sqliteman and Qt4 Designer, there the fonts are not affected.

My graphics card is an NVIDIA GTX 960 (GM206 chip). The behavior happens both with the proprietary NVIDIA driver (from the negativo17 repository), as well as with the open source nouveau driver.

A workaround is to disable subpixel rendering:

ln -s /usr/share/fontconfig/conf.avail/10-no-sub-pixel.conf /etc/fonts/conf.d/


Please also pay attention to the text within the TeXstudio window in the attached screenshot: 
Only the currently active line that is highlighted has distorted fonts. The lines above and below look perfectly fine.


Also note that VLC uses a different theme or something when using the Nouveau driver than when using the Nvidia driver. The other two tested applications however are still affected, regardless of the driver that is used.


Version-Release number of selected component (if applicable):
qt5-qtbase-5.9.2-4.fc27.x86_64

kernel-4.13.12-300.fc27.x86_64

dkms-nvidia-387.22-1.fc27.x86_64
nvidia-driver-libs-387.22-2.fc27.i686
nvidia-driver-libs-387.22-2.fc27.x86_64
nvidia-settings-387.22-1.fc27.x86_64
nvidia-libXNVCtrl-387.22-1.fc27.x86_64
nvidia-driver-387.22-2.fc27.x86_64
nvidia-driver-cuda-libs-387.22-2.fc27.x86_64



How reproducible:
Every time

Steps to Reproduce:
1. Open any Qt5 application

Actual results:
Distorted fonts

Expected results:
Not distorted fonts


Additional info:
The problem is reported against Fedora 27, but it also happened under Fedora 26.

Comment 1 Rex Dieter 2017-11-20 14:13:27 UTC
For completeness, I'd encourage you to re-test with rpmfusion's freetype-freeworld package installed.  Mostly to know if that makes any difference or not.

Second test item: systemsettings->fonts
under use-anti-aliasing -> configure -> sub-pixel rendering type:
Try different options there, RGB, BGR, ... to see if that makes any difference too.

Comment 2 Rex Dieter 2017-12-14 14:03:24 UTC
ping ^^, I'll keep this open for another week for so waiting for feedback

(otherwise, since nvidia isn't anything fedora ships and without evidence this isn't an nvidia driver bug, we may have to close this CANTFIX anyway)

Comment 3 Alexander Korsunsky 2017-12-16 14:17:45 UTC
Hi! Sorry that it took so long.

Installing the freetype-freeworld package helped, fonts are normal now.

I don't know what you mean by "systemsettings", but if you mean gnome-control-center, then I could not find font settings there.
If you meant gnome-tweak-tool, then there are only three options there:

Subpixel (for LCD screens)
Standard (greyscale)
none

Without the freetype-freeworld, the first one causes the distortion while the other two options do not.

Comment 4 Ben Cotton 2018-11-27 15:15:03 UTC
This message is a reminder that Fedora 27 is nearing its end of life.
On 2018-Nov-30  Fedora will stop maintaining and issuing updates for
Fedora 27. It is Fedora's policy to close all bug reports from releases
that are no longer maintained. At that time this bug will be closed as
EOL if it remains open with a Fedora  'version' of '27'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 27 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Comment 5 Ben Cotton 2018-11-30 21:55:06 UTC
Fedora 27 changed to end-of-life (EOL) status on 2018-11-30. Fedora 27 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this
bug.

Thank you for reporting this bug and we are sorry it could not be fixed.


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